1株黑天鹅源H5N8亚型禽流感病毒遗传演化分析

Genetic Evolution Analysis of A H5N8 Subtype Avian Influenza Virus Isolated from Black Swan

为分析1株黑天鹅源H5N8亚型禽流感病毒(AIV)的遗传演化特征,对2021年从北京圆明园遗址公园送检的黑天鹅样品中鉴定出的1株H5N8亚型禽流感病毒(A/Wild swan/China/Beijing0201/2021)的全基因组进行扩增、克隆与序列测序,并应用分子生物学软件对其进行遗传演化及关键氨基酸位点分析。结果显示,该H5N8亚型禽流感病毒株属于clade2.3.4.4b进化分支,其PB2、PB1、PA、HA、NA、NP、MP、NS基因均与H5N8亚型AIV的相应基因片段具有较高同源性,且与2020-2021年越南、哈萨克斯坦、俄罗斯、柬埔寨、法国等地的H5N8毒株密切相关。氨基酸位点分析显示,该毒株HA蛋白裂解位点呈现高致病性禽流感病毒的分子特征,且出现S137A、T160A、T192I、S227R氨基酸突变,158位缺失糖基化位点,这些位点的突变均能够增强H5亚型禽流感病毒对人源唾液酸受体结合的能力;该毒株的PB2蛋白、NP蛋白、M1蛋白和NS1蛋白均存在多个可以增强流感病毒在哺乳动物体内的复制能力和致病性的关键氨基酸位点。研究结果可为H5N8亚型禽流感病毒的进化规律研究及综合防控提供参考。

To analyze the genetic evolution characteristics of a strain of H5N8 subtype avian influenza virus(AIV)isolated from black swan,the complete genomic sequences of a strain of H5N8 subtype avian influenza virus(A/Wild swan/China/Beijing0201/2021)identified from the black swan samples collected by Beijing Yuanmingyuan park in 2021 were amplified,cloned and sequenced.The genetic evolution and key amino acid sites were analyzed by molecular biology software.The results showed that the H5N8 subtype avian influenza virus strain belonged to clade 2.3.4.4b evolutionary branch.The PB2,PB1,PA,HA,NP,NA,MP and NS genes were highly homologous with the corresponding genes of H5N8 subtype AIV,and the strain was closely related to the H5N8 strains found in Vietnam,Kazakhstan,Russia,Cambodia and France from 2020 to 2021.Amino acid site analysis showed that the HA protein cleavage site of this strain had the molecular characteristics of highly pathogenic avian influenza virus,contained the amino mutations of S137A,T160A,T192I and S227R,with the deletion of glycosylation sites at the 158th position,and mutations of these sites could enhance the binding ability of H5 subtype avian influenza virus to human sialic acid receptors.The PB2 protein,NP protein,M1 protein and NS1 protein of this strain all had several key amino acid sites that can enhance the replication ability and pathogenicity of influenza virus in mammals.This study provided experimental basis for the study on the evolution and comprehensive prevention and control of H5N8 subtype avian influenza virus.